Conveyor handrails

ABSTRACT

A variable speed handrail for a conveyor in which a series of relatively slidable overlapping elements provides a load bearing surface in the edge regions. The elements may slide transversely or slide in other directions simultaneously with a change of inclination. The handrail may follow a curved or straight path and a constant depth handrail is provided. The relative sliding is controlled by guide means and drive means are provided as well as positive means for maintaining the elements in mutual contact, of which the following is a specification.

United States Patent 1 [111 3,714,902

Zuppiger Feb. 6, 1973 I CONVEYOR HANDRAIL 3,583,325 6/1971 Melin ..|04/25 [75] Inventor: Paul pp g Geneva, Switzerland l,7l8,085 6/1929 Sene ..lO4/25 [73] Assignees: Dunlop Holdings Limited; Battelle Primary ExaminerGerald M. Forlenza Memorial Institute, Geneve, Swit- Assistant ExaminerD. W. Keen zerland Att0rneyStevens, Davis, Miller & Mosher {22] Filed: Aug. 24,1971 ABSTRACT [21] Appl' l74426 A variable speed handrail for a conveyor in which a series of relatively slidable overlapping elements pro- [30] Foreign Application Priority Data vides a load bearing surface in the edge regions. The elements may slide transversely or slide in other Aug. 27, l970 Switzerland ..l2795/7O directions Simultaneously a change f inclination. The handrail may follow a curved or straight path and [52] U.S. Cl ..104/25, l98/l l0, l98/l6 R a constant depth handrail i provided The relative [5]] lllt. Cl ..B65g 17/06 sliding is controlled by guide means and drive means [58] new of Search "104/18, 25; gs/l are provided as well as positive means for maintaining 198/16 MS, l6, 18 the elements in mutual contact, of which the following is a specification. [56] References Cited 36 Claims, 45 Drawing Figures UNITED STATES PATENTS 3.580,l82 5/1971 Bouladon ..l04/25 or 1 FEB Sign SHEET 02 PAIENTE r I]! g a; ill

FIG.

PATENTEUFEB SHEET [BM 16 MOI J I I I'll/Ir w PATENTEDFEB' 6 I973 SHEET GEN 16 Pmmnmmslm 3.714302 SHEET UBUF 16 PATENTED FEB 6 I973 SHEET 070F 16 FIG-9 FIGIO PATENTED FEB 6 I975 SHEET 08 0F 16 FIG.

XIV

FIG. l3

PATENTED FEB 6 l975 SHEET USUF 16 PATENTED FEB 6 I975 SHEET 110F 16 FIG 27 PATENTEU 6|973 3,714,902

snm' lSUF 16 PAIENTEI] FEB 6 I975 sum 1B or 16 CONVEYOR HANDRAILS This invention relates to handrails for variable speed conveyors such as are used for conveying passengers. Such handrails may also be provided for conveyors carrying goods for the use of service personnel.

Several types of conveyors having a variable speed zone are known. Such conveyors commonly comprise a series of platforms and different platforms move, at different points in the conveyor circuit, at different speeds. One such conveyor is described in our copending patent application (SB DA 569) to which reference may be made for further details.

It is essential for passenger conveyors, to promote passenger confidence and for safety reasons, to provide a suitable handrail.

The handrail should provide a generally smooth, easily held rail which moves at all times in the passenger carrying zone at the same speed as the platforms to which it is adjacent. Such an arrangement is easily made for a constant speed conveyor by means of a continuous handrail of the type used for escalators. Hitherto variable speed devices have utilized handrails in which a section of the handrail is mechanically connected to each platform. Such arrangements do not, however, provide a handrail which has a smoothly varying speed and whilst it may be satisfactory for a standing passenger they do not meet the necessary conditions for a handrail for a passenger who is walking.

It is an object of the present invention to provide a handrail which has a smoothly changing speed in the speed change zones of the conveyor.

According to one aspect of the present invention a handrail for a balustrade of a conveyor having at least one variable speed zone, comprises a series of relatively slidable overlapping elements having a load bearing surface in edge regions of the elements, guide means for the elements, and drive means for the elements whereby in the variable speed zone the degree of overlapping of the elements is changed to produce a speed variation for the elements.

According to another aspect of the invention the degree of overlap of the elements is controlled by the said guide means.

According to yet another aspect of the invention the elements are arranged to project from a balustrade and present to passengers a substantially constant depth handrail assembly comprising the edge regions of the elements.

According to still another aspect of the invention the edges of the elements in the load bearing edge regions are chamfered such that changes in the degree of overlap do not cause trapping of passengers.

Yet a further aspect provides a handrail wherein the variable speed zone is curved, the elements are arranged to be substantially parallel to one another over a substantial length of the handrail and the overlap is varied in a lateral direction with respect to the direction of movement of the handrail.

The guide means preferably comprises two generally parallel guide rails which engage slots one at either side of each element. The slots may be T-shaped to retain the elements on the guide rails and anti-friction means may be used.

The elements may be driven by a screw having a variable pitch external thread which engages a projecting pin on the elements. Hinge links may be provided between the projecting pins and provide an alternative drive means. Other drive means may also be utilized such as linear motors or toothed sprocket wheels engaging the hinge links.

Another aspect provides means of retaining the elements together.

Another aspect of the invention provides a handrail having elements comprising a rigid central web to each side of which is attached a layer of compressible material whereby adjacent elements may be relatively changed in orientation. Such elements are preferably precompressed on assembly of the handrail and allow a handrail having a curved path or a variable speed handrail which has a straight path.

Still another aspect of the invention provides a handrail wherein the elements are inclined and the inclination is varied simultaneously with the sliding by the guide means and drive means.

Yet another aspect of the invention provides variable pitch drive screw which is flexible such that it may follow the path of the handrail and provide a substantially continuous drive for the elements.

Further aspects of the invention will become apparent from the following description of some embodiments of the inventions, by way of example only, in conjunction with the accompanying diagrammatic drawings in which:

FIG. 1 is a plan showing the position of the handrails on a conveyor;

FIG. 2 is a plan on a larger scale of the low speed zone A of FIG. 1;

FIG. 3 is a plan on a larger scale of the high speed zone B of FIG. 1;

FIG. 4 is a detail cross-sectional view of the handrail in the low speed zone A of FIG. 1;

FIG. 5 is a detail cross-sectional view of the handrail in the high speed zone B of FIG. 1;

FIG. 6 is a cross-section ofa first drive system for the elements;

FIG. 7 shows the drive system of FIG. 6 in side elevation;

FIG. 8 is a plan ofa drive screw;

FIGS. 9 and 10 are a cross-section and longitudinal section of the drive screw of FIG. 8;

FIGS. 11 and 12 show one method of interlocking the elements;

FIGS. 13 and 14 show an alternative method ofinterlocking the elements;

FIG. 15 shows an alternative drive system;

FIGS. 16 is a section on the lines XVIXVI of FIG. 15;

FIGS. 17 shows a linear motor drive system in crosssection;

FIGS. 18 shows yet another drive system using drive wheels;

FIG. 19 is a section on the line XIX-XIX of FIG. 18;

FIGS. 20 and 21 show alternative element shapes;

FIG. 22 shows a handrail having an acceleration and deceleration zone;

FIG. 23 is a cross-section of another form of element;

FIG. 24 is a plan view of a constant speed handrail having a curved path;

FIG. 25 is a plan view of a straight line variable speed handrail;

FIG. 26 is a plan of another form of handrail running alongside a conveyor;

FIG. 27 is a side elevation of the handrail of FIG. 26;

FIG. 28 is an enlarged view of the acceleration zone of FIG. 27;

FIG. 29 is a perspective view of an element of the handrail of FIG. 26;

FIG. 30 is a front view of the element of FIG. 29;

FIG. 31 is a view on line XXXI-XXXI of FIG. 30;

FIG. 32 is a view on the line XXXII-XXXII of FIG. 30;

FIG. 33 is a detail section on the line XXXIII--XXX- III of FIG. 32;

FIG. 34 is a side elevation of a drive system for the elements of the handrail of FIG. 26 in the slow speed zone;

FIG. 35 is a cross-section on the line XXXV- XXXV of FIG. 34; 7

FIG. 36 is a transverse section of part of a stack of elements showing the interlocking systems;

FIG. 37 shows the elements of FIG. 34 in the variable speed zone;

FIG. 38 shows the elements of FIG. 34 in the high speed zone;

FIG. 39 is a plan view in the direction of the arrow T- in FIG. 38;

FIG. 40 is a view on the line XVXV of FIG. 38;

FIG. 41 shows a side elevation of another form of handrail in the low speed zone;

FIG. 42 shows the handrail of FIG. 41 in the high speed zone;

FIG. 43 is a section on the line XLIIl- -XLIII of FIG. 42;

FIG. 44 is a view in the direction U of FIG. 41;

FIG. 45 is a part section to shown an alternative guide means for the elements.

As illustrated in FIG. 1 a platform conveyor comprises a series of platforms 1 which move in a curved path and accelerates from a speed V in a low-speed zone 2 to a speed n V0 in a high speed zone 3. The platforms in the high-speed zone are arranged to run adjacent to and at the same speed as a constant speed belt 4. The arrangement is such that passengers stepping onto the platform in the low speed zone 2 are smoothly accelerated into the high-speed zone 3 whereupon the passengers step onto the constant speed belt. Details of the platform arrangement and operation are given in our co-pending patent application (SB DA 569) to which further reference should be made.

Handrails 5, 6 are provided one at either side of the passenger carrying area of the platforms 1 and the handrails are arranged to have the same speed as the platforms. The handrail 5 terminates where the platforms 1 meet the high-speed belt 4 but the handrail 6 continues at least until passenger transference is completed as described in the above mentioned specification.

Each handrail 5, 6 comprises a series of many metal elements in the form of plates 7 in juxtaposition and as shown in FIGS. 2 and 3. Each plate 7 comprises an inverted T-shaped outline as shown in FIG. 4. The lower straight edge 8 of which has two slots 9 and 10 of T- shaped outline which engage guide rails 11 and 12. Each guide rail has a supporting column 13 and a head 14 which is a sliding fit in the slots 9, 10. At the center of the edge 8 is attached a downwardly protruding steel drive pin 15 which acts as an engagement element for the drive means.

The remainder of the profile of the plate 7 is shaped to provide a central hand hold 16 and two side hand holds 17 for engagement by passengers hands as shown.

The guide rails 11, 12 are mounted at the top of a ba- 'lustrade 18 one of which is provided at each side of the conveyor in a similar manner to those on escalators and the effect of the plates 7 in side-by-side relationship is to form a longitudinally extending rail. As each plate is thin only small steps occur and thus the rail presents a reasonably smooth hand hold for passengers. The edges of each plate 7 are rounded or chamfered to remove any chance of trapping skin or clothing during use of the conveyor.

FIGS. 2 and 3 illustrate the low and high speed regions A and B respectively of FIG. 1 and the positions of the plates 7 in each may be seen. In the low speed zone (FIG. 2) the plates 7 are substantially perpendicular to the handrail center-line whereas in the high speed zone (FIG. 3) the plates are at an acute angle to the handrail center-line which has of course changed in direction due to the curved path. Just as in the case of the platforms 1 the plates 7 are at first driven in the direction D of FIG. 1 and are then accelerated in the direction E until, having slid one over the other, they form a lengthened assembly moving at high-speed in the high-speed zone 3. The plates 7 themselves maintain substantially a constant angular position with regard to a fixed datum direction (e.g. center-line of the high-speed belt 4).

The movements of the plates 7 is controlled by the guide rails 11,12 which become closer together as the plates 7 are accelerated. The spacing shown in FIG. 4 is that in the low-speed zone and FIG. 5 shows the spacing in the high-speed zone. The guide rails 11,12 form a tensioned loop, of which a part of the length is used to recycle the elements and connects the high-speed end of each hand rail to the impart of the low-speed end at the platform position 2.

The plates 7 are maintained in their close packed relationship by magnetic attraction. The two side portions 17 of each plate 7 are magnetized, one north and one south, and then the plates are stacked such that adjacent plates 7 place unlike magentic poles together. The ensuing magnetic attraction holds the plates together and prevents the formation of gaps in the rail.

The drive of the many plates 7 comprising each handrail is by means of an endless screw as shown in FIGS. 6 and 7. A flexible cylindrical screw 19 has provided an external thread 20 extending along its length as shown in FIG. 8 and support bearings are provided along the length of the screw at unthreaded portions 21 and at least one drive motor 22 with belt connecting means 23 is provided so that the screw 19 may be driven.

As shown in FIGS. 9 and 10 the screw 19 comprises a central core 24 in the form of a metal cable with the strands wound in opposite directions to give a balanced assembly. Between the unthreaded portions 21 the core is covered by a layer 25 of rubber which is vulcanized onto the core. An outer cylinder 26 of plastic is bonded over the rubber layer 25 and the thread is machined in the plastic cylinder 26. The resultant screw assembly 19 is flexible and may therefore be arranged between a series of bearing assemblies 21 to follow the required curvature. The thread base pitch increases towards the high-speed zone 3 and thus as the plates 7 slide into their more greatly staggered positions of the high-speed zone 3 the screw 19 continuously drives each plate by means of its central drive pin which engages the screw 19. The increasing pitch of the thread is arranged to give the same handrail speed as platform speed so that any platform is alongside the same portion of handrail throughout its load bearing zones.

The return run of the handrail comprises a similar drive and support system and at each end the guiderails follows a large radius path such that the rail passes into and out of the passenger zones similar to a normal escalator handrail.

The plates 7 may be of materials other than metal for example wood or synthetic material. If the materials are not magnetic, magnets may be incorporated or alternatively other interengaging means may be used.

In the embodiment shown in FIGS. 11 and 12 the two side portions 17 of each plate 7 are different. One side has pieced a circular aperture 28 and the other has pieced a slot 29. The elements are stacked (as shown in FIG. 12) such that moving down the stack holes and slots alternate at each side. Into each hole is inserted a headed rivet-like member of steel such that each plate 7 is retained to the previous one, a countersink 29a being provided to allow clearance for the rivet head to move. Thus for the requisite movement between the plates 7 the rivets 30 move in the slots 29.

The arrangement shown in FIGS. 13 and 14 comprises a longitudinal groove 32 across one lateral face of each plate 7 and on the other face a rib 33 of complimentary cross-section to the groove in the manner of a dovetail. Assembly into the groove 32 of the rib 33 locks the plates together without restricting the required lateral sliding. Assembly may be assisted by temporarily bending the plates such that the groove 32 is opened and the rib 33 may be inserted. (The length of each groove 32 must be greater than the rib to allow the sliding).

Alternative drive means may be used. To begin with drive pegs 15 need only be provided on some plates 7 relying on interaction between the plates to push the intermediate undriven plates 7. Another drive system is shown in FIGS. 15 and 16.

In this arrangement a series of levers 34 forms a chain. The levers 34 are hinged in pairs and on each hinge of each pair is mounted a pair of rollers 35. One end 36 of each pair of levers is connected to a second pair of rollers 38 mounted to the drive pin 15 of a plate 7 and the other end 37 of the pair oflevers is connected to a pair of rollers 38 mounted to the next drive pin 15. Thus the spaced apart drive pins are connected by the levers. The second pair of rollers 38 run on an upper roller track 39 and the first pair of rollers run on a lower roller track 40 which is arranged below the upper track. The distance between the tracks thus controls the spacing between adjacent drive pins and this spacing is arranged, as is the variable pitch thread of the first embodiment to correspond with the spacing composed by the curved path and the guide rails 11 and 12. The chain is driven by means of a chain wheel, not shown, which engages the chain at a portion of its path at which it does not drive plates.

Another drive system is shown in section in FIG. 17. In this arrangement the plates 7 are metallic and mounted in a recess in the upper portion of the balustrade 18 are arranged a sequence of field coils 41 such that the metal plates form the armature of a linear motor drive system.

Yet another drive system is shown in FIGS. 18 and 19 in which a series of powered wheels 42-47 is arranged in sequence under the handrail. Each wheel is in frictional contact with the lower surface edges of the plates 7. The diameters of the wheels are graduated so that the same rotational speed of a set of wheels (e.g. wheels 43-47 which are linked by drive shafts 50) provides increasing peripheral speeds as required for the accelerating handrail. The motor 48 drives a first set of wheels ending at 42 and the motor 49 drives the set 43-47 shown.

In the above description, all the plates 7 slide on the guide rails 11,12 which means the drive system chosen must be sufficiently powerful to overcome quite high frictional losses. These losses may be reduced by various means such as forming a film of air between the slots 9 and 10 and the guide rails 11 and 12 or magnetizing an area of each plate 7 and each guide rail to produce repulsion and thus some magnetic support.

Various plate shapes may be utilized and two alternative shapes are shown in FIGS. 20 and 21. The actual shape used depends on the size of rail required and the various passengers to be accommodated e.g. children or adults or both.

A handrail and conveyor as described may be run in either direction as either an accelerator, as described, or a decelerator. Alternatively, as in FIG. 22, the device may curve back again and decelerate following the high speed zone. Such an arrangement and combination with various high speed belts to give loading and unloading stations are described in our co-pending application No. SB.DA.5 69.

The handrails so far described have utilized mutual sliding and a curved path without any change in orientation to produce the acceleration or deceleration. The curvature illustrated being parabolic gives a smooth acceleration but it is quite possible to use other curvatures, in which case a variable acceleration is obtained. Furthermore the invention is not limited to curved paths and a curved constant speed or a straight path, variable speed handrail may also be made as will now be described in conjunction with FIGS. 23, 24 and 25.

FIG. 23 shows a single modified plate 52 in vertical section. The modified plate 52 comprises a central rigid web 53 and its two side faces are covered by layers 54, 55 of synthetic foam covered by a resistant plastics skin 56 of low coefficient of friction.

A series of such modified plates 52 may be rocked relative to their longitudinal axes as well as relatively slid over each other. This allows the center of gravity of each element to momentarily follow a circular patch of large radius without changing its longitudinal position relative to the adjacent elements as shown in FIG. 23. Thus as shown in FIG. 24 the handrail may be arranged to follow a path curved in the horizontal plane. To avoid the creation of gaps during such movements the stack of modified plates 52 is subjected to an axial precompression. This is made sufficient such that in a curved portion of the path no gaps are formed on the outer curved surface of the handrail. 

1. A handrail for a balustrade of a conveyor having at least one variable speed zone, comprising: a series of relatively slidable overlapping elements having a load bearing surface in edge regions of the elements, guide means for the elements, and drive means for the elements whereby in the variable speed zone the degree of overlapping of the elements is changed to produce a speed variation for the elements.
 1. A handrail for a balustrade of a conveyor having at least one variable speed zone, comprising: a series of relatively slidable overlapping elements having a load bearing surface in edge regions of the elements, guide means for the elements, and drive means for the elements whereby in the variable speed zone the degree of overlapping of the elements is changed to produce a speed variation for the elements.
 2. A handrail as in claim 1 wherein the degree of overlap of the elements is controlled by the said guide means.
 3. A handrail as in claim 2 wherein the elements are arranged to project from a balustrade and present to passengers a substantially constant depth handrail assembly comprising the edge regions of the elements.
 4. A handrail as in claim 2 wherein the edges of the elements in the load bearing edge regions are chamfered so that changes in the degree of overlap do not cause trapping of passengers.
 5. A handrail as in claim 2 wherein the variable speed zone is curved, the elements are arranged to be substantially parallel to one another over a substantial length of the handrail and the overlap is varied in a lateral direction with respect to the direction of movement of the handrail.
 6. A handrail as in claim 5 wherein the guide means comprises two generally parallel guide rails engaging slots, one at either side of each element and the spacing of the two guide rails is varied to maintain the elements mutually parallel around the curve by sliding to change the degree of overlapping.
 7. A handrail as in claim 6 wherein the guide rails and slots are generally T-shaped so that the elements are retained on the guide rails.
 8. A handrail as in claim 6 wherein at least some of the elements have provided projecting engagement means whereby the elements may be driven along the guide rails.
 9. A handrail as in claim 8 wherein the engagement means comprises a pin projecting from an edge of an element and the drive means comprises a longitudinally extending variable pitch screw having an external thread into which the pin is engaged to provide a drive means for the elements.
 10. A handrail as in claim 8 wherein the engagement means comprises a pin projecting from an edge of an element and succeeding pins are connected by a hinged link member pivotally connected to each pin, each pin and each hinge comprises a set of rollers for engaging one of two guide rails the first said guide rail guiding the rollers on the engagement pins and the second said guide rail running spaced from the first guide rail and guiding the rollers of the hinges whereby he spacing of the guide rails is varied such that the hinged link members and the guide rails each serve to provide the change in overlap of the elements in the variable speed zone.
 11. A handrail as in claim 10 wherein the link members are engaged by a toothed wheel at an end of the handrail run and the said toothed wheel provides drive means for the elements through the medium of the roller and link mechanism.
 12. A handrail as in claim 8 wherein the engagement means comprise an armature for a linear motor arranged in the edge of the balustrade between the guide rails whereby the elements are driven along the guide rails.
 13. A handrail as in claim 8 wherein the engagement means provideS a substantially flat surface and roller drive means are provided whereby drive is obtained by frictional drive from the rollers to the elements.
 14. A handrail as in claim 13 wherein the successive rollers are of increasing diameter and all the rollers are driven at the same rotational speed whereby the peripheries of the rollers move at increasing speed as required to accelerate the elements.
 15. A handrail as in claim 2 wherein each element comprises at least in part a magnetized region and the series of elements is assembled such that the elements are retained in mutual contact by magnetic attraction.
 16. A handrail as in claim 2 wherein the elements are mechanically retained together to prevent the formation of gaps between the edge region of adjacent elements.
 17. A handrail as in claim 16 wherein the mechanical lock is by means of a headed stud attached to an element and engaging the next element through a slot so that sliding is not restricted.
 18. A handrail as in claim 16 wherein the mechanical lock is by means of a lateral groove on one surface of each element and a projecting ridge on the other surface, the said groove and ridge being if complementary interengaging cross-sections such that the elements are retained together and sliding is not restricted.
 19. A handrail as in claim 2 wherein each element comprises a rigid central web to each side of which is attached a layer of compressible material whereby adjacent elements may be relatively changed in orientation.
 20. A handrail as in claim 19 wherein the guide rails for the handrail follow a curved path and the handrail elements change in relation orientation to allow the said curvature by virtue of compression of the material without a substantial speed change.
 21. A handrail as in claim 19 wherein the handrail follows a substantially straight path through a variable speed zone and the change in the degree of overlapping is by means of the guide rail spacing changing so that each element is progressively changed in orientation with respect to its direction of movement, the said compressible means allowing the movement without the formation of gaps at the edge regions.
 22. A handrail as in claim 19 wherein the elements comprising the handrail are precompressed on assembly to prevent the formation of gaps at the outer edges during changes of orientation.
 23. A handrail as in claim 2 wherein the elements are inclined and the inclination is varied simultaneously with the sliding by the guide means and drive means.
 24. A handrail as in claim 23 wherein each element comprises two parallel plate members connected by s step such that the two plate members extend in spaced apart parallel planes and interengagement means are provided whereby adjacent elements are retained in contact over at least part of the area of each plate member without impairing the relative sliding.
 25. A handrail as in claim 24 wherein the interengagement means comprises two pins each having enlarged head portions for engaging two parallel slots on one plate member of an adjacent element the slots extending in the direction of the relative sliding between the elements.
 26. A handrail as in claim 24 wherein a transverse shaft is provided attached to each element, the shaft extending in a direction parallel to the plate members and spaced from the planes of the said plate members, the shaft providing projections at either side of the element which engage guide slots provided on the balustrade of the handrail.
 27. A handrail as in claim 24 wherein a series of links connect the elements the links being fully extended when the elements are in the most widely spaced portion as in the high speed zone of the conveyor the said links then serving to power the elements along the conveyor.
 28. A handrail as in claim 27 wherein the links comprise steel tapes.
 29. A handrail as in claim 23 wherein an engagement lever projects from each element adapted to engage a drive screw, the said screw runninG adjacent the elements forming the handrail and having a variable pitch and a constant speed drive means whereby the engagement levers of the elements are driven at different speeds in different zones of the handrail and the spacing inclination and overlapping of adjacent elements is determined by the screw pitch.
 30. A handrail as in claim 2 wherein the elements are driven by a variable pitch screw the said variable pitch screw being flexible and mounted in a series of spaced apart bearings such that it follows the path of the handrail so that it may continuously engage the elements.
 31. A handrail as in claim 30 wherein the screw comprises a central flexible steel cable core, a resilient layer of elastomeric material and an outer covering layer of plastics material, the thread groove being formed in the outer covering layer.
 32. A handrail as in claim 31 wherein the spaced apart bearings each comprise three axially rotatably rollers mounted at points around the screw with their rotational axes parallel to the axis of the flexible screw at the position of the bearing the said rollers each contacting the periphery of the screw and at least one of the said rollers being powered whereby drive is transmitted to the screw.
 33. A handrail as in claim 32 wherein for at least one of the said bearings an endless belt passes around the outside of the three rollers and around the outer surface of the screw against which it is held in driving contact by the inner faces of the three rollers.
 34. A handrail as in claim 23 wherein each element comprises a plate which is substantially flat in the edge regions, provided with a projecting outer limb member at each of two opposite sides of the plate, each limb having a projecting bearing pin for engaging guide means comprising a slot at either edge of the balustrade, and an operating arm extending outwardly from the plane of the plate and limb members and having engagement means for engaging a second guide means spaced from the first guide means whereby changing of the spacing between the said guide means slides the edge regions of the elements with respect to one another and changes the inclination of the elements to allow a change in the length of the assembly and a speed change.
 35. A handrail as in claim 34 wherein hinged link members connect the operating arms of adjacent elements, the links extending in opposite directions between successive elements guide pins through each hinge engaging first and second control guides the control guides being spaced apart and the spacing being changed in the variable speed zones so that the operating arms are spaced apart by the links to slide and incline the elements to change the degree of overlapping. 